1. Field of the Invention
The invention relates to a common module, and more particularly to a common module for a double data rate-synchronous II synchronous dynamic random access memory (DDRII SDRAM) and a DDRIII SDRAM.
2. Description of the Related Art
Double data rate-synchronous III synchronous dynamic random access memories (DDRIII SDRAMs) have been developed to meet the requirements of high transfer rate and low power consumption. The operating voltage of a DDRIII SDRAM has been reduced over the previous generation from 2.5V to 1.8V, thus, power consumption has been correspondingly reduced, resulting in longer operating life of application devices (such as computers and mobile phones). Additionally, the DDRIII SDRAM packaging techniques, pins, and signals have also improved over previous generations.
FIG. 1 shows a conventional main board of a DDRII SDRAM. In FIG. 1, a DDRII SDRAM 11 is installed in a DDRII slot of a main board 1. A main controller 10 provides data signals DATA, address signals ADD, and control signals CMD to the DDRII SDRAM 11. The main controller 10 can be an Intel north bridge chipset or an AMD central processing unit (CPU). Referring to FIG. 1, termination resistors RADD and RCMD required for the address signals ADD and the control signals CMD are disposed on the main board 1, and termination resistors RDATA for the data signals DATA are built into the DDRII SDRAM 11.
FIG. 2 shows a conventional main board of a DDRIII SDRAM. In FIG. 2, a DDRIII SDRAM 21 is installed in a DDRIII slot of a main board 2. A main controller 20 provides data signals DATA, address signals ADD, and control signals CMD to the DDRIII SDRAM 21. The main controller 20 can be an Intel north bridge chipset or an AMD CPU. Referring to FIG. 2, termination resistors RDATA, RADD, and RCMD required for the data signals DATA, the address signals ADD, and the control signals CMD are built into the DDRIII SDRAM 21. Compared with the main board 1 of the DDRII SDRAM 11 in FIG. 1, the termination resistors RADD and RCMD of the DDRIII SDRAM 21 are removed from the main board 2 and disposed inside the DDRIII SDRAM 21.
As described, the specifications of a DDRII SDRAM and a DDRIII SDRAM are different. When a DDRII SDRAM or a DDRIII SDRAM is used selectively, a different main board is required for each.
A common module for a DDRII SDRAM and a DDRIII SDRAM is thus provided. The common module allows selective use of a DDRII SDRAM or a DDRIII SDRAM without requiring two main boards having different specifications.